![]() ![]() If needed, I could remove the 10 pF and substitute a 5 pF or 15 pF capacitor to fine tune the match. I mounted a 47 pF NP0 ceramic SMT capacitor in the BNC connector itself, followed by a 15 pF and 10 pF parallel NP0 SMT capacitors on the protoboard that the matching network was built on. The mounted BNC showed around 7 pF capacitance, leaving about 71 pF of additional capacitance. I also measured the capacitance of the BNC connector using the nanoVNA and verifying with an autozeroing small capacitance meter. ![]() ![]() This made me decide to use a set of parallel capacitors so I could fine tune the value that will provide a close match, this turned out to be a good decision. Large changes in capacitor value will prevent the match to be close to the chart center, no matter the value of the inductor. Changes in the capacitor value keeps the network from moving along the 50 ohm constant resistance curve to the center. The most sensitive value seemed to be the capacitor. Initially I looked at how the match varies with changes in the component values. ![]()
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